docs: def getManager(self, force=False):
          """Extract the YadisServiceManager for this object's URL and
          suffix from the session.
  
          @param force: True if the manager should be returned
          regardless of whether it's a manager for self.url.
  
          @return: The current YadisServiceManager, if it's for this
              URL, or else None
          """
          manager = self.session.get(self.getSessionKey())
          if (manager is not None and (manager.forURL(self.url) or force)):
              return manager
          else:
              return None